A battery often energizes a powered surgical tool used in an operating room to perform a surgical procedure. The use of a battery eliminates the need to provide a power cord connected to an external power source. The elimination of the power cord offers several benefits over corded surgical tools. Surgical personnel using this type of tool do not have to concern themselves with either sterilizing a cord so that it can be brought into the sterile surgical field surrounding the patient or ensuring that, during surgery, an unsterilized cord is not inadvertently introduced into the sterile field. Moreover, the elimination of the cord results in the like elimination of the physical clutter and field-of-view blockage the cord otherwise brings to a surgical procedure.
In an operating room, batteries are used to power more than the tools used to perform the surgical procedure. Batteries are also used to energize the power consuming components integral with a personal protection system surgical personnel sometimes wear when performing a procedure. This system typically includes some type of hooded garment. Internal to the garment is a ventilation unit for circulating air within the garment. Some of these systems also have lights for illuminating the surgical site or radios that facilitate conventional spoken level conversation with other persons involved in performing the procedure. Each of these units, the ventilation unit, the light unit and the radio, requires a source of power. By providing this power from the battery, the need to attach cords to each individual wearing such a unit is eliminated. This reduces number of cords in the operating room personnel would otherwise have to avoid. Further, eliminating these cords likewise eliminates the restrictions of movement they place on the individual using the system.
Many batteries used in the operating room include rechargeable cells. This allows the battery to be repetitively used. Typically, the cells are bound together to form a cell cluster.
To reduce, if not eliminate, the possibility of patient infection, it is necessary to sterilize any object introduced into the sterile field. (Generally, the “sterile field” is the space surrounding the surgical site at which the procedure is performed. The sterile field extends to the front of the surgeon and assisting personnel.) This requirement extends to the batteries used to charge surgical tools employed to perform the procedure. Typically, a battery is sterilized by placement in an autoclave. In the autoclave, the battery is subjected to an atmosphere saturated with water vapor (steam), the temperature is approximately 270° F. and the atmospheric pressure is approximately 30 psi (Gage).
One disadvantage of the above process is that exposure to the heat in the autoclave damages the cells. This is especially true if, the battery is autoclaved for time periods of 10 minutes or more. Some sterilization protocols require batteries for this period of time, if not longer.
To prevent autoclave-induced cell damage, some batteries are provided with removable cell clusters. This type of battery includes a housing with a void space for accommodating the cells. The housing also includes a moveable cover that encloses the cells in the void space. This allows the cell cluster to be removed from the housing prior to the autoclave process. Once the housing is sterilized and cells charged, the cluster is fitted into the housing. Once the process is complete, the surgical personnel have available for use a fully charged and autoclaved sterilized battery.
The above batteries perform reasonably in that they provide charges to devices that are used in sterile environments. However, the known batteries tend to be large in size. This reduces the ergonomics associated with working with these batteries. Further, the cell clusters internal to these batteries are often known to require custom fixtures of sockets for attaching them to the complementary chargers to which they are fitted. The Applicants' Assignee's U.S. Pat. No. 6,018,227, BATTERY CHARGER ESPECIALLY USEFUL WITH STERILIZABLE RECHARGEABLE BATTERY PACKS, issued Jan. 25, 2000 and incorporated herein by reference, discloses that it is possible to provide a charger with separate socket-forming modules for use with different types of battery assemblies. Thus, the known systems require the entity supplying the charger, and sometimes the facility using the batteries, to maintain a supply of chargers or modules with different shaped sockets.